<template>
	<div class="todo-footer">
		<label>
			<input type="checkbox" v-model="isAll" />
		</label>
		<span>
			<span>已完成{{doneTotal}}</span> / 全部{{total}}
		</span>
		<button @click="handleClear" class="btn btn-danger">清除已完成任务</button>
	</div>
</template>

<script>
	export default {
		name:'Footer',
		props:['todos','checkAll','clearAllDone'],
		methods:{
			handleClear(){
				console.log('@')
				this.clearAllDone()
			}
		},
		computed:{
			//总数
			total(){
				return this.todos.length
			},
			//已完成的总数
			doneTotal(){
				return this.todos.reduce((pre,item)=> pre + (item.done ? 1 : 0),0)
			},
			//是否全选
			isAll:{
				get(){
					return this.total === this.doneTotal && this.total > 0
				},
				set(value){
					//通知App去修改所有todo项的done值
					this.checkAll(value) //此处的checkAll其实是App里的
				}
			}
		}
	}
</script>

<style scoped>
	/*footer*/
	.todo-footer {
		height: 40px;
		line-height: 40px;
		padding-left: 6px;
		margin-top: 5px;
	}
	.todo-footer label {
		display: inline-block;
		margin-right: 20px;
		cursor: pointer;
	}
	.todo-footer label input {
		position: relative;
		top: -1px;
		vertical-align: middle;
		margin-right: 5px;
	}
	.todo-footer button {
		float: right;
		margin-top: 5px;
	}
</style>